At a summit meeting in Washington, D.C. on Monday, the U.S. and South Korean presidents will discuss modernizing their 71-year-old alliance and fleshing out a trade deal reached last month.

A deal with the White House to help Trump revive US shipbuilding offers a risky route to expansion for South Korean yards.

On his first official visit to Japan since taking office in June, Lee met Ishiba at the premier's residence in Tokyo to discuss bilateral ties between the East Asia neighbours, including closer security coordination with the United States under a trilateral pact signed by their predecessors.